ncursesw-morphos/doc/html/man/curs_util.3x.html
Thomas E. Dickey ce4803687b ncurses 6.0 - patch 20170218
+ fix several formatting issues with manual pages.
+ correct read of terminfo entry in which all strings are absent or
  explicitly cancelled.  Before this fix, the result was that all were
  treated as only absent.
+ modify infocmp to suppress mixture of absent/cancelled capabilities
  that would only show as "NULL, NULL", unless the -q option is used,
  e.g., to show "-, @" or "@, -".
2017-02-19 02:52:26 +00:00

418 lines
22 KiB
HTML

<!--
* t
****************************************************************************
* Copyright (c) 1998-2015,2017 Free Software Foundation, Inc. *
* *
* Permission is hereby granted, free of charge, to any person obtaining a *
* copy of this software and associated documentation files (the *
* "Software"), to deal in the Software without restriction, including *
* without limitation the rights to use, copy, modify, merge, publish, *
* distribute, distribute with modifications, sublicense, and/or sell *
* copies of the Software, and to permit persons to whom the Software is *
* furnished to do so, subject to the following conditions: *
* *
* The above copyright notice and this permission notice shall be included *
* in all copies or substantial portions of the Software. *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
* IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
* THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
* *
* Except as contained in this notice, the name(s) of the above copyright *
* holders shall not be used in advertising or otherwise to promote the *
* sale, use or other dealings in this Software without prior written *
* authorization. *
****************************************************************************
* @Id: curs_util.3x,v 1.47 2017/02/18 16:43:03 tom Exp @
-->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<HTML>
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="generator" content="Manpage converted by man2html - see http://invisible-island.net/scripts/readme.html#others_scripts">
<TITLE>curs_util 3x</TITLE>
<link rev=made href="mailto:bug-ncurses@gnu.org">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</HEAD>
<BODY>
<H1 class="no-header">curs_util 3x</H1>
<PRE>
<STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG> <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
<STRONG>delay_output</STRONG>, <STRONG>filter</STRONG>, <STRONG>flushinp</STRONG>, <STRONG>getwin</STRONG>, <STRONG>key_name</STRONG>, <STRONG>keyname</STRONG>,
<STRONG>nofilter</STRONG>, <STRONG>putwin</STRONG>, <STRONG>unctrl</STRONG>, <STRONG>use_env</STRONG>, <STRONG>use_tioctl</STRONG>, <STRONG>wunctrl</STRONG> -
miscellaneous <STRONG>curses</STRONG> utility routines
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>
<STRONG>char</STRONG> <STRONG>*unctrl(chtype</STRONG> <STRONG>c);</STRONG>
<STRONG>wchar_t</STRONG> <STRONG>*wunctrl(cchar_t</STRONG> <STRONG>*c);</STRONG>
<STRONG>char</STRONG> <STRONG>*keyname(int</STRONG> <STRONG>c);</STRONG>
<STRONG>char</STRONG> <STRONG>*key_name(wchar_t</STRONG> <STRONG>w);</STRONG>
<STRONG>void</STRONG> <STRONG>filter(void);</STRONG>
<STRONG>void</STRONG> <STRONG>nofilter(void);</STRONG>
<STRONG>void</STRONG> <STRONG>use_env(bool</STRONG> <STRONG>f);</STRONG>
<STRONG>void</STRONG> <STRONG>use_tioctl(bool</STRONG> <STRONG>f);</STRONG>
<STRONG>int</STRONG> <STRONG>putwin(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>FILE</STRONG> <STRONG>*filep);</STRONG>
<STRONG>WINDOW</STRONG> <STRONG>*getwin(FILE</STRONG> <STRONG>*filep);</STRONG>
<STRONG>int</STRONG> <STRONG>delay_output(int</STRONG> <STRONG>ms);</STRONG>
<STRONG>int</STRONG> <STRONG>flushinp(void);</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
</PRE><H3><a name="h3-unctrl">unctrl</a></H3><PRE>
The <STRONG>unctrl</STRONG> routine returns a character string which is a
printable representation of the character <EM>c</EM>, ignoring at-
tributes. Control characters are displayed in the <STRONG>^</STRONG><EM>X</EM> no-
tation. Printing characters are displayed as is. The
corresponding <STRONG>wunctrl</STRONG> returns a printable representation
of a wide character.
</PRE><H3><a name="h3-keyname_key_name">keyname/key_name</a></H3><PRE>
The <STRONG>keyname</STRONG> routine returns a character string correspond-
ing to the key <EM>c</EM>:
<STRONG>o</STRONG> Printable characters are displayed as themselves,
e.g., a one-character string containing the key.
<STRONG>o</STRONG> Control characters are displayed in the <STRONG>^</STRONG><EM>X</EM> notation.
<STRONG>o</STRONG> DEL (character 127) is displayed as <STRONG>^?</STRONG>.
<STRONG>o</STRONG> Values above 128 are either meta characters (if the
screen has not been initialized, or if <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> has
been called with a <STRONG>TRUE</STRONG> parameter), shown in the <STRONG>M-</STRONG><EM>X</EM>
notation, or are displayed as themselves. In the lat-
ter case, the values may not be printable; this fol-
lows the X/Open specification.
<STRONG>o</STRONG> Values above 256 may be the names of the names of
function keys.
<STRONG>o</STRONG> Otherwise (if there is no corresponding name) the
function returns null, to denote an error. X/Open al-
so lists an "UNKNOWN KEY" return value, which some im-
plementations return rather than null.
The corresponding <STRONG>key_name</STRONG> returns a character string cor-
responding to the wide-character value <EM>w</EM>. The two func-
tions do not return the same set of strings; the latter
returns null where the former would display a meta charac-
ter.
</PRE><H3><a name="h3-filter_nofilter">filter/nofilter</a></H3><PRE>
The <STRONG>filter</STRONG> routine, if used, must be called before <STRONG>initscr</STRONG>
or <STRONG>newterm</STRONG> are called. The effect is that, during those
calls, <STRONG>LINES</STRONG> is set to 1; the capabilities <STRONG>clear</STRONG>, <STRONG>cup</STRONG>,
<STRONG>cud</STRONG>, <STRONG>cud1</STRONG>, <STRONG>cuu1</STRONG>, <STRONG>cuu</STRONG>, <STRONG>vpa</STRONG> are disabled; and the <STRONG>home</STRONG>
string is set to the value of <STRONG>cr</STRONG>.
The <STRONG>nofilter</STRONG> routine cancels the effect of a preceding
<STRONG>filter</STRONG> call. That allows the caller to initialize a
screen on a different device, using a different value of
<STRONG>$TERM</STRONG>. The limitation arises because the <STRONG>filter</STRONG> routine
modifies the in-memory copy of the terminal information.
</PRE><H3><a name="h3-use_env">use_env</a></H3><PRE>
The <STRONG>use_env</STRONG> routine, if used, should be called before
<STRONG>initscr</STRONG> or <STRONG>newterm</STRONG> are called (because those compute the
screen size). It modifies the way <STRONG>ncurses</STRONG> treats environ-
ment variables when determining the screen size.
<STRONG>o</STRONG> Normally <STRONG>ncurses</STRONG> looks first at the terminal database
for the screen size.
If <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> for parameter, it
stops here unless If <STRONG>use_tioctl</STRONG> was also called with
<STRONG>TRUE</STRONG> for parameter.
<STRONG>o</STRONG> Then it asks for the screen size via operating system
calls. If successful, it overrides the values from
the terminal database.
<STRONG>o</STRONG> Finally (unless <STRONG>use_env</STRONG> was called with <STRONG>FALSE</STRONG> parame-
ter), <STRONG>ncurses</STRONG> examines the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> environ-
ment variables, using a value in those to override the
results from the operating system or terminal data-
base.
<STRONG>Ncurses</STRONG> also updates the screen size in response to
SIGWINCH, unless overridden by the <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG>
environment variables,
</PRE><H3><a name="h3-use_tioctl">use_tioctl</a></H3><PRE>
The <STRONG>use_tioctl</STRONG> routine, if used, should be called before
<STRONG>initscr</STRONG> or <STRONG>newterm</STRONG> are called (because those compute the
screen size). After <STRONG>use_tioctl</STRONG> is called with <STRONG>TRUE</STRONG> as an
argument, <STRONG>ncurses</STRONG> modifies the last step in its computa-
tion of screen size as follows:
<STRONG>o</STRONG> checks if the <STRONG>LINES</STRONG> and <STRONG>COLUMNS</STRONG> environment variables
are set to a number greater than zero.
<STRONG>o</STRONG> for each, <STRONG>ncurses</STRONG> updates the corresponding environ-
ment variable with the value that it has obtained via
operating system call or from the terminal database.
<STRONG>o</STRONG> <STRONG>ncurses</STRONG> re-fetches the value of the environment vari-
ables so that it is still the environment variables
which set the screen size.
The <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> routines combine as summarized
here:
<EM>use</EM><STRONG>_</STRONG><EM>env</EM> <EM>use</EM><STRONG>_</STRONG><EM>tioctl</EM> <EM>Summary</EM>
----------------------------------------------------------------
TRUE FALSE This is the default behavior. <STRONG>ncurses</STRONG>
uses operating system calls unless over-
ridden by $LINES or $COLUMNS environment
variables.
TRUE TRUE <STRONG>ncurses</STRONG> updates $LINES and $COLUMNS
based on operating system calls.
FALSE TRUE <STRONG>ncurses</STRONG> ignores $LINES and $COLUMNS, us-
es operating system calls to obtain
size.
FALSE FALSE <STRONG>ncurses</STRONG> relies on the terminal database
to determine size.
</PRE><H3><a name="h3-putwin_getwin">putwin/getwin</a></H3><PRE>
The <STRONG>putwin</STRONG> routine writes all data associated with window
(or pad) <EM>win</EM> into the file to which <EM>filep</EM> points. This
information can be later retrieved using the <STRONG>getwin</STRONG> func-
tion.
The <STRONG>getwin</STRONG> routine reads window related data stored in the
file by <STRONG>putwin</STRONG>. The routine then creates and initializes
a new window using that data. It returns a pointer to the
new window. There are a few caveats:
<STRONG>o</STRONG> the data written is a copy of the <STRONG>WINDOW</STRONG> structure,
and its associated character cells. The format dif-
fers between the wide-character (ncursesw) and non-
wide (ncurses) libraries. You can transfer data be-
tween the two, however.
<STRONG>o</STRONG> the retrieved window is always created as a top-level
window (or pad), rather than a subwindow.
<STRONG>o</STRONG> the window's character cells contain the color pair
<EM>value</EM>, but not the actual color <EM>numbers</EM>. If cells in
the retrieved window use color pairs which have not
been created in the application using <STRONG>init_pair</STRONG>, they
will not be colored when the window is refreshed.
</PRE><H3><a name="h3-delay_output">delay_output</a></H3><PRE>
The <STRONG>delay_output</STRONG> routine inserts an <EM>ms</EM> millisecond pause
in output. This routine should not be used extensively
because padding characters are used rather than a CPU
pause. If no padding character is specified, this uses
<STRONG>napms</STRONG> to perform the delay.
</PRE><H3><a name="h3-flushinp">flushinp</a></H3><PRE>
The <STRONG>flushinp</STRONG> routine throws away any typeahead that has
been typed by the user and has not yet been read by the
program.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
Except for <STRONG>flushinp</STRONG>, routines that return an integer re-
turn <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> (SVr4 specifies only "an in-
teger value other than <STRONG>ERR</STRONG>") upon successful completion.
Routines that return pointers return <STRONG>NULL</STRONG> on error.
X/Open does not define any error conditions. In this im-
plementation
<STRONG>flushinp</STRONG>
returns an error if the terminal was not initial-
ized.
<STRONG>putwin</STRONG>
returns an error if the associated <STRONG>fwrite</STRONG> calls
return an error.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
</PRE><H3><a name="h3-filter">filter</a></H3><PRE>
The SVr4 documentation describes the action of <STRONG>filter</STRONG> only
in the vaguest terms. The description here is adapted
from the XSI Curses standard (which erroneously fails to
describe the disabling of <STRONG>cuu</STRONG>).
</PRE><H3><a name="h3-keyname">keyname</a></H3><PRE>
The <STRONG>keyname</STRONG> function may return the names of user-defined
string capabilities which are defined in the terminfo en-
try via the <STRONG>-x</STRONG> option of <STRONG>tic</STRONG>. This implementation auto-
matically assigns at run-time keycodes to user-defined
strings which begin with "k". The keycodes start at
KEY_MAX, but are not guaranteed to be the same value for
different runs because user-defined codes are merged from
all terminal descriptions which have been loaded. The
<STRONG>use_extended_names</STRONG> function controls whether this data is
loaded when the terminal description is read by the li-
brary.
</PRE><H3><a name="h3-nofilter_use_tioctl">nofilter/use_tioctl</a></H3><PRE>
The <STRONG>nofilter</STRONG> and <STRONG>use_tioctl</STRONG> routines are specific to
<STRONG>ncurses</STRONG>. They were not supported on Version 7, BSD or
System V implementations. It is recommended that any code
depending on <STRONG>ncurses</STRONG> extensions be conditioned using
NCURSES_VERSION.
</PRE><H3><a name="h3-putwin_getwin">putwin/getwin</a></H3><PRE>
The <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG> functions have several issues with
portability:
<STRONG>o</STRONG> The files written and read by these functions use an
implementation-specific format. Although the format
is an obvious target for standardization, it has been
overlooked.
Interestingly enough, according to the copyright dates
in Solaris source, the functions (along with <STRONG>scr_init</STRONG>,
etc.) originated with the University of California,
Berkeley (in 1982) and were later (in 1988) incorpo-
rated into SVr4. Oddly, there are no such functions
in the 4.3BSD curses sources.
<STRONG>o</STRONG> Most implementations simply dump the binary <STRONG>WINDOW</STRONG>
structure to the file. These include SVr4 curses,
NetBSD and PDCurses, as well as older <STRONG>ncurses</STRONG> ver-
sions. This implementation (as well as the X/Open
variant of Solaris curses, dated 1995) uses textual
dumps.
The implementations which use binary dumps use block-
I/O (the <STRONG>fwrite</STRONG> and <STRONG>fread</STRONG> functions). Those that use
textual dumps use buffered-I/O. A few applications
may happen to write extra data in the file using these
functions. Doing that can run into problems mixing
block- and buffered-I/O. This implementation reduces
the problem on writes by flushing the output. Howev-
er, reading from a file written using mixed schemes
may not be successful.
</PRE><H3><a name="h3-unctrl_wunctrl">unctrl/wunctrl</a></H3><PRE>
The XSI Curses standard, Issue 4 describes these func-
tions. It states that <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a
null pointer if unsuccessful, but does not define any er-
ror conditions. This implementation checks for three cas-
es:
<STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is the
case that X/Open Curses documented.
<STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1 con-
trol code. If <STRONG>use_legacy_coding</STRONG> has been called with
a <STRONG>2</STRONG> parameter, <STRONG>unctrl</STRONG> returns the parameter, i.e., a
one-character string with the parameter as the first
character. Otherwise, it returns "~@", "~A", etc.,
analogous to "^@", "^A", C0 controls.
X/Open Curses does not document whether <STRONG>unctrl</STRONG> can be
called before initializing curses. This implementa-
tion permits that, and returns the "~@", etc., values
in that case.
<STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unctrl</STRONG>
returns a null pointer.
The strings returned by <STRONG>unctrl</STRONG> in this implementation are
determined at compile time, showing C1 controls from the
upper-128 codes with a "~" prefix rather than "^". Other
implementations have different conventions. For example,
they may show both sets of control characters with "^",
and strip the parameter to 7 bits. Or they may ignore C1
controls and treat all of the upper-128 codes as print-
able. This implementation uses 8 bits but does not modify
the string to reflect locale. The <STRONG>use_legacy_coding</STRONG> func-
tion allows the caller to change the output of <STRONG>unctrl</STRONG>.
Likewise, the <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> function allows the caller to
change the output of <STRONG>keyname</STRONG>, i.e., it determines whether
to use the "M-" prefix for "meta" keys (codes in the range
128 to 255). Both <STRONG>use_legacy_coding</STRONG> and <STRONG>meta</STRONG> succeed only
after curses is initialized. X/Open Curses does not docu-
ment the treatment of codes 128 to 159. When treating
them as "meta" keys (or if <STRONG>keyname</STRONG> is called before ini-
tializing curses), this implementation returns strings
"M-^@", "M-^A", etc.
</PRE><H3><a name="h3-use_env_use_tioctl">use_env/use_tioctl</a></H3><PRE>
If <STRONG>ncurses</STRONG> is configured to provide the sp-functions ex-
tension, the state of <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> may be updat-
ed before creating each <EM>screen</EM> rather than once only
(<STRONG><A HREF="curs_sp_funcs.3x.html">curs_sp_funcs(3x)</A></STRONG>). This feature of <STRONG>use_env</STRONG> is not pro-
vided by other implementation of curses.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
<STRONG><A HREF="legacy_coding.3x.html">legacy_coding(3x)</A></STRONG>, <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>, <STRONG>curs_in-</STRONG>
<STRONG><A HREF="curs_inopts.3x.html">opts(3x)</A></STRONG>, <STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>, <STRONG><A HREF="curs_scr_dump.3x.html">curs_scr_dump(3x)</A></STRONG>,
<STRONG><A HREF="curs_sp_funcs.3x.html">curs_sp_funcs(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG><A HREF="legacy_coding.3x.html">legacy_coding(3x)</A></STRONG>.
<STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-unctrl">unctrl</a></li>
<li><a href="#h3-keyname_key_name">keyname/key_name</a></li>
<li><a href="#h3-filter_nofilter">filter/nofilter</a></li>
<li><a href="#h3-use_env">use_env</a></li>
<li><a href="#h3-use_tioctl">use_tioctl</a></li>
<li><a href="#h3-putwin_getwin">putwin/getwin</a></li>
<li><a href="#h3-delay_output">delay_output</a></li>
<li><a href="#h3-flushinp">flushinp</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a>
<ul>
<li><a href="#h3-filter">filter</a></li>
<li><a href="#h3-keyname">keyname</a></li>
<li><a href="#h3-nofilter_use_tioctl">nofilter/use_tioctl</a></li>
<li><a href="#h3-putwin_getwin">putwin/getwin</a></li>
<li><a href="#h3-unctrl_wunctrl">unctrl/wunctrl</a></li>
<li><a href="#h3-use_env_use_tioctl">use_env/use_tioctl</a></li>
</ul>
</li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
</BODY>
</HTML>